:root {
    --prime-color:#13227a
}

body {
    width: 780px;
    margin: 0 auto;
}

p {
    font-size: 18px;
    text-indent: 2em;
    text-align: justify;
}

pre {
    font-family: "Noto Serif SC";
    font-weight: 700;
    font-size: 18px;
    line-height: 1.5;
    color: wheat(188,45,183);
    letter-spacing: 1px;
}

h1 {
    color: var(--prime-color)
}

h2 {
    text-decoration: underline;
    color: rgb(117,86,86);
    background-image: url(resourse/img/sheep.svg;);
    background-repeat: no-repeat;
    background-size: 35px;
    padding-left: 35px;
    margin: 40px auto 20px;
}

.abstract p {
    background-color: rgb(91,121,147);
    background: linear-gradient(to right bottom,rgb(91,121,147),rgb(183,206,226));
    padding: 1em;
    margin: 8px auto;
    border: 1px solid var(--prime-color);
    border-radius: 4px 16px;
}

.abstract p {
    font-size: 13px;
    line-height: 2;
}

.extra {
    background-image: url(resource/img/bg-demo.jpg);
    border: 5px solid var(--prime-color);
    border-radius: 16px 16px;
    background-size: 50% 100%;
}